Bcl-2 associated transcription factor 1 promotes proliferation but inhibits self-renewal of embryonic spinal cord neural stem/progenitor cells through enhancing the mammalian target of rapamycin complex 1 signaling

Abstract

Abstract Background Spinal cord neural stem/progenitor cells (NSPCs) have great potential to reconstitute damaged spinal neural circuitry. However, the mechanisms regulating their activities have not been thoroughly understood. In this study, we revealed the expression and function of Bcl-2-associated transcription factor 1 (BCLAF1) in mouse NSPCs. Methods Mouse embryonic spinal cord NSPCs were cultured in vitro. Lentivirus-mediated Bclaf1 knockdown was conducted. After Bclaf1 knockdown, NSPC apoptosis and proliferation were measured by Annexin V staining and Ki67 staining, respectively. NSPC self-renewal was analyzed by the serial passage assay. NSPC multipotentcy was evaluated by the NSPC differentiation assay. The expression of molecules key to NSPC proliferation and differentiation was measured by real-time RT-PCR and Immunoblotting. Respectively. Results BCLAF1 knockdown inhibited NSPC proliferation but enhanced NSPC self-renewal. BCLAF1 knockdown significantly down-regulated the protein levels of Cyclin D1 and Cyclin E1 in NSPCs. Furthermore, BCLAF1 knockdown abrogated the activation of mammalian target of rapamycin complex 1 (mTORC1) via decreasing the transcript levels of mammalian target of rapamycin (mTOR) and regulatory-associated protein of mammalian target of rapamycin (Raptor). The mTOR activator MHY1485 partially restored NSPC proliferation. However, BCLAF1 seemed not to affect NSPC differentiation into neurons and astroglia. Conclusions BCLAF1 promotes spinal cord NSPC proliferation but inhibits spinal cord NSPC self-renewal through enhancing the mTORC1 signaling.